LTE (Long Term Evolution) is a standard for wireless communications. Data transmission capability and speed are improved under LTE, due to the usage of new technologies and modulation methods. As such, LTE is taken as the mainstream interim technology supported by many carries all over the world.
However, it is still very common that both the LTE and the 2G/3G technologies, such as GSM (Global System for Mobile Communication) and TD-SCDMA (Time Division-Synchronous Code Division Multiple Access), are existed in one mobile terminal at the same time. Furthermore, in some countries, such as China, given advantages on speed and cost, the WLAN (Wireless Local Area Networks) technology has been widely used and become an indispensable part of mobile terminal devices.
Accordingly, the mobile terminal device has to be able to support multiple wireless communication technologies. For example, one mobile terminal device has to support the 2G/3G technology and the WLAN technology at the same time. Or, one mobile terminal device has to support the LTE technology and the WLAN technology at the same time. In the wireless spectrum, 2G/3G, WLAN and LTE have frequency bands close to or even neighboring to each other. Therefore, interferences among these wireless communications are unavoidable, which may cause performance degradation of the mobile terminal device.
In existing mobile terminal devices, filters are often used to reduce interferences among different wireless communication modes and prevent such interferences from degrading performance of other wireless communication modes. However, this kind of method is costly and usually not sufficient to repress interferences between adjacent frequency bands.